Wastewater treatment control system, terminal, computer program and accounting method

ABSTRACT

A wastewater treatment control system for controlling a wastewater treatment of using a microorganism that can degrade a specific compound, comprises measuring a specific value corresponding to a concentration of the specific compound in wastewater, and controlling the wastewater treatment on the basis of the specific value.

The present application is a divisional of co-pending U.S. patentapplication Ser. No. 10/379,729 filed on Mar. 6, 2003 for which priorityis claimed under 35 U.S.C. § 120; and the present application claimspriority of Patent Application No. 2002-061020 filed in Japan on Mar. 6,2002 and Patent Application No. 2002-190496 filed in Japan on Jun. 28,2002, under 35 U.S.C. § 119. The entire contents of each of theseapplications are herein fully incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a wastewater treatment control system,a terminal associated with it, a computer program and an accountingmethod to wastewater treatment service. In particular, the inventionrelates to a wastewater treatment control system for controlling from aremote place a plurality of treatment tanks in which wastewater istreated, a terminal, a computer program and an accounting method.

BACKGROUND OF THE INVENTION

In general, activated sludge treatment has been conducted for treatmentof organic compounds in industrial wastewater. In recent years, however,compounds that can not be degraded by conventional activated sludgetreatment, for example, hardly biodegradable chelating agents includingEDTA, organic chlorine compounds including trihalomethanes, and varioussurfactants of nonyl phenol derivatives, are discharged into nature,which presents a social problem from fear of environmental pollution andan increased burden on the environment. It is difficult to biodegradethese compounds by the conventional activated sludge process, andparticularly, when the compounds exist at a high concentration (forexample, 200 ppm or more), the adverse effect thereof is profound.

For example, the above-mentioned hardly biodegradable chelating agentsare generally used in industrial soap, the photographic industry, thepulp industry and the plating industry. Wastewater containing suchhardly biodegradable materials has a high COD value. However, suchmaterials are not degraded by the conventional activated sludgetreatment. Accordingly, as a method for treating the wastewater, adilution method of reducing the concentration of the materials to aneffluent control value or less by diluting the wastewater with differentwater has most generally been used.

In addition, recovery incineration treatment has also been used in somecases.

However, in the dilution method, the cost of water is high, and thetotal amount of the hardly biodegradable material discharged is notdecreased. Further, in the recovery incineration method, the burden ofthe treating cost is further increased.

For this reason, a treating method of degrading the hardly biodegradablematerial with a microorganism has been developed, as a wastewatertreating method low in the treating cost and essentially decreasing thetotal amount of the hardly biodegradable material contained. However, insuch a treating method, it is difficult to control the microorganism. Inparticular, when a plurality of treatment tanks are installed, it isnecessary to control activity of the microorganism in each tank. Itbecomes therefore necessary to control the wastewater treatment by anexpert. However, it is actually difficult to independently conduct it byeach factory unit.

In addition, when the treatment is conducted by mixing a particularmicroorganism that can degrade the hardly biodegradable compound in aconventional activated sludge tank, it is very difficult to controlconditions under which both the microorganism already existing in theactivated sludge tank and the particular microorganism newly introducedtherein are brought into action. In general, the existing microorganismbecomes predominant, and activity of the latter microorganism is loweredin many cases. Accordingly, in such a mixed system, it is necessary tocontrol the conditions for sustaining activity of each microorganism. Itbecomes therefore necessary to control the wastewater treatment by anexpert. However, it is actually difficult to independently conduct it byeach factory unit.

Further, in the field of business relating to degradation of hardlybiodegradable compounds with microorganisms, rewards have hitherto beenreaped by selling the microorganisms. However, the microorganisms areeasily proliferated under specific conditions. Accordingly, once themicroorganisms are sold, it becomes unnecessary that the purchasers buythem again. The problem is therefore encountered that the wastewatertreatment business utilizing such microorganisms for wastewatertreatment is not feasible as business. It is therefore a reality that apositive search of the microorganisms for this purpose has not beenconducted.

SUMMARY OF THE INVENTION

Then, an object of the invention is to provide a control method that cansolve the above-mentioned problems and execute control by an expert froma remote place. Another object of the invention is to provide a centralcontrol device for conducting the control method. Still another objectof the invention is to provide a program for a computer executing thecontrol. A further object of the invention is to provide an accountingmethod relating to the execution thereof. These objects are eachattained by a combination of features described in each independentclam. Further, each dependent claim specifies a more advantageousspecific example of the invention.

Another object of the invention is to provide a wastewater treatmentcontrol system that can execute wastewater treatment control essentiallyreducing the total amount of a hardly biodegradable material, at lowcost and moreover even from a remote place. Still another object of theinvention is to provide a central control device therefor. Still anotherobject of the invention is to provide a wastewater treatment controlprogram. A further object of the invention is to provide an accountingmethod relating to the execution thereof.

In the following description of this specification, the term“biodegradation” is also briefly referred to as “degradation”, the term“hardly degradable” as “hardly degradable”, the term “hardlybiodegradable compound” as “specific compound”, and the term“microorganism that can degrade the hardly biodegradable compound, thatis to say, the specific compound” as “specific microorganism”.

The above-mentioned objects are attained by the following constructionsand a combination thereof. That is to say, the invention provides thefollowings.

(1) A wastewater treatment control system for controlling a treatmenttank for treating wastewater with a microorganism that can degrade aspecific compound, which comprises: a terminal for obtaining datarelating to the treatment tank; and a central control devicecommunicating with the terminal through a network,

wherein the terminal has: a concentration-measuring unit for measuring aconcentration value corresponding to a concentration of the specificcompound in the treatment tank; and a transmitting unit for transmittingthe concentration value measured by the concentration-measuring unit tothe central control device, and

the central control device receives the concentration value of thetreatment tank from the terminal.

(2) The specific compound means a compound hardly degradable withcommonly used activated sludges which include miscellaneousmicroorganisms.

(3) Further, the treatment tank may have two or more tanks.

(4) A terminal connected through a network to a central control devicefor controlling a treatment tank for treating wastewater with amicroorganism that can degrade a specific compound, the terminalcomprising: a concentration-measuring unit for measuring a concentrationcorresponding to a concentration of the specific compound in thetreatment tank; and a transmitting unit for transmitting theconcentration value measured by the concentration-measuring unit to thecentral control device.

(5) A program for a computer connected through a network to a centralcontrol device for controlling a treatment tank for treating wastewaterwith a microorganism that can degrade a specific compound, wherein theprogram allows the computer to realize: a concentration measuringfunction of measuring a concentration corresponding to a concentrationof the specific compound in the treatment tank; and a transmittingfunction of transmitting the concentration value measured to the centralcontrol device.

(6) A method of accounting for a wastewater treatment service with thewastewater treatment control system according to any one of the items(1) to (5), which comprises accounting in proportion to a reduction incost by introduction of the wastewater treatment system, compared tocost previously required for draining wastewater.

(7) A central control device for controlling a plurality of treatmenttanks for treating wastewater in which the treatment tanks are locatedin a place physically apart from the central control device, whichcomprises:

a receiving unit for receiving: a concentration value corresponding to aconcentration of a specific compound in each of the treatment tanksbefore treatment; and a concentration value corresponding to aconcentration of the specific compound after treatment, so that theconcentration values are associated with each of the treatment tanks;

a computing unit for computing a difference between the concentrationvalue before treatment and the concentration value after treatmentreceived by the receiving unit; and

a concentration storing unit for storing difference informationindicating the difference between the concentration value beforetreatment and the concentration value after treatment computed by thecomputing unit.

(8) The central control device according to the item (7), wherein amicroorganism for degrading a material contained in wastewater is addedto each treatment tank, and the central control device comprises: astoring unit for storing microorganism-specifying information forspecifying the microorganism, so that the information is associated witheach of the treatment tanks; and a totaling unit for summarizing thedifference between the concentration before treatment and theconcentration after treatment computed by the computing unit, for eachidentical microorganism-specifying information.

The totaling unit may further have an output unit for outputting thetotaled information summarized thereby.

(9) A central control device for controlling a plurality of treatmenttanks for treating wastewater, which comprises:

a predetermined value-storing unit for storing a predetermined valuedetermined on the basis of a concentration value corresponding to aconcentration of a specific compound in each of the treatment tanks, sothat the predetermined value is associated with each of the treatmenttanks,

a receiving unit for receiving difference information specifying adifference between a concentration of the specific compound beforetreatment and a concentration of the specific compound after treatment;

a comparison unit for comparing the difference between the concentrationbefore treatment and the concentration after treatment specified by thedifference information received by the receiving unit, to thepredetermined value stored in the predetermined value-storing unit; and

a processing unit for conducting predetermined treatment on the basis ofthe results of comparison by the comparison unit.

(10) A program for a computer for controlling a plurality of treatmenttanks for treating wastewater, in which the treatment tanks is locatedin buildings physically apart from each other,

wherein the program allows the computer to realize: a receiving functionof receiving a concentration value corresponding to a concentration of aspecific compound before treatment and a concentration valuecorresponding to a concentration of the specific compound aftertreatment; a computing function of computing a difference between theconcentration before treatment and the concentration after treatmentwhich have been received; and a concentration-controlling function ofcontrolling difference information indicating the computed differencebetween the concentration before treatment and the concentration aftertreatment.

(11) A program for a computer for controlling a plurality of treatmenttanks for treating wastewater, wherein the program allows the computerto realize:

a predetermined value-control function of controlling a predeterminedvalue determined on the basis of a concentration of a specific compoundin each of the treatment tanks, so that the predetermined value isassociated with each of the treatment tanks;

a receiving function of receiving difference information specifying adifference between a concentration of the specific compound beforetreatment and a concentration of the specific compound after treatment;

a comparison function of comparing a difference between a concentrationvalue corresponding to the concentration before treatment and aconcentration value corresponding to the concentration after treatment,in which the difference is specified by the difference informationreceived, to the predetermined value that has been controlled; and

a processing function of conducting a predetermined treatment on thebasis of the results of comparison by the comparison function.

(12) A wastewater treatment control system for controlling a wastewatertreatment of using an activated sludge tank containing a microorganismthat can degrade a hardly biodegradable compound, in which the systemcomprises: a measuring unit for measuring a BOD value and acharacteristic value corresponding to a concentration of the hardlybiodegradable compound in wastewater; and a controlling unit forcontrolling the wastewater treatment on the basis of the BOD value andthe characteristic value.

(13) A wastewater treatment control system for controlling a wastewatertreatment of using an activated sludge tank containing a microorganismthat can degrade a hardly biodegradable compound,

wherein the system comprises a terminal for obtaining data for controland a central control device communicating with the terminal through acommunication network,

the terminal has: a measuring unit for measuring a BOD value and acharacteristic value corresponding to a concentration of the hardlybiodegradable compound as the data for control; and a transmitting unitfor transmitting the data for control measured by the measuring unit tothe central control device, and

the central control device receives the data for control from theterminal and controls the wastewater treatment on the basis of the datareceived.

(14). The wastewater treatment control system according to the items(12) or (13), wherein the activated sludge tank comprises two or moretanks.

(15) A terminal connected through a communication network to a centralcontrol device for controlling a wastewater treatment of using anactivated sludge tank containing a microorganism that can degrade ahardly biodegradable compound, wherein the terminal comprises: ameasuring unit for measuring a BOD value and a characteristic valuecorresponding to a concentration of the hardly biodegradable compound inthe activated sludge tank; and a transmitting unit for transmitting theBOD value and the characteristic value, which are measured by themeasuring unit, to the central control device.

(16) A program for a computer connected through a communication networkto a central control device for controlling a wastewater treatment ofusing an activated sludge tank containing a microorganism that candegrade a hardly biodegradable compound, wherein the program allows thecomputer to realize: a concentration measuring function of measuring aBOD value and a characteristic value corresponding to a concentration ofthe hardly biodegradable compound in the activated sludge tank; and atransmitting function of transmitting the BOD value and thecharacteristic value measured to the central control device.

(17) A method of accounting for a wastewater treatment service with thewastewater treatment control system according to claim 12, whichcomprises accounting in proportion to a reduction in treatment cost byintroduction of the wastewater treatment system, compared to treatmentcost previously required for draining wastewater.

(18) A central control device that can remotely control a plurality ofwastewater treatment tanks for treating wastewater, in which thewastewater treatment tanks are located in a place physically apart fromthe central control device, wherein the central control devicecomprises:

a receiving unit for receiving a BOD value and a characteristic valuecorresponding to a concentration of a hardly biodegradable compound ineach of the treatment tanks before treatment, and a BOD value and acharacteristic value corresponding to a concentration of the hardlybiodegradable compound in each of the treatment tanks after treatment,so that the values are associated with each of the treatment tanks;

a computing unit for computing a difference between the BOD valuesreceived by the receiving unit before and after treatment, and adifference between the characteristic values before and after treatment;and

a difference information storing unit for storing difference informationindicating the difference between the BOD values before and aftertreatment and the difference between the characteristic values beforeand after treatment, which have been computed by the computing unit.

(19) The central control device according to the item (18), wherein amicroorganism for degrading a material contained in wastewater is addedto each of the treatment tanks, and the central control devicecomprises: a storing unit for storing microorganism-specifyinginformation for specifying the microorganism, so that the information isassociated with each of the treatment tanks; and a totaling unit forsummarizing the difference between the BOD values before and aftertreatment and the difference between the characteristic values beforeand after treatment, which have been computed by the computing unit, foreach identical microorganism-specifying information.

The totaling unit may further have an output unit for outputting thetotaled information summarized thereby.

(20) A central control device for controlling a plurality of treatmenttanks for treating wastewater, which comprises:

a predetermined value-storing unit for storing a predetermined valuedetermined on the basis of a BOD value and a characteristic valuecorresponding to a concentration of a specific compound in each of thetreatment tanks, so that the predetermined value is associated with eachof the treatment tanks;

a receiving unit for receiving difference information specifying adifference between the BOD values before and after treatment and adifference between the characteristic values before and after treatment,respectively;

a comparison unit for comparing the difference between the BOD valuesbefore and after treatment and the difference between the characteristicvalues before and after treatment, which are specified by the differenceinformation received by the receiving unit, to the predetermined valuestored in the predetermined value-storing unit; and

a processing unit for conducting predetermined wastewater treatment onthe basis of the results of comparison by the comparison unit.

(21) A program for a computer for controlling a plurality of treatmenttanks for treating wastewater, in which the treatment tanks are locatedin buildings physically apart from each other, wherein the programallows the computer to realize: a receiving function of receiving BODvalues and characteristic values corresponding to concentrations of aspecific compound before and after treatment; a computing function ofcomputing a difference between the BOD values before and after treatmentand a difference between the characteristic values before and aftertreatment, which have been received; and a concentration-controllingfunction of controlling difference information indicating the differencebetween the BOD values before and after treatment and the differencebetween the characteristic values before and after treatment, which havebeen computed.

(22) A program for a computer for controlling a plurality of treatmenttanks for treating wastewater, wherein the program allows the computerto realize: a predetermined value control function of controlling eachpredetermined value determined on the basis of a BOD value and aconcentration of a hardly biodegradable compound in each of thetreatment tanks, so that the predetermined value is associated with eachof the treatment tanks; a receiving function of receiving differenceinformation specifying a difference between the BOD values before andafter treatment and a difference between the concentrations of thehardly biodegradable compound before and after treatment in each of thetreatment tanks; a comparison function of comparing the differencebetween the BOD values before and after treatment, and the differencebetween the concentrations of the hardly biodegradable compound beforeand after treatment, which are specified by the difference informationreceived, to the predetermined value that is controlled; and aprocessing function of conducting predetermined treatment on the basisof the results of comparison by the comparison function.

The above-mentioned respective aspects do not enumerate all of thefeatures of the wastewater treatment control system, the terminalassociated with it, the computer program and the accounting method forwastewater treatment service, which are necessary for the invention. Theinvention also includes combinations of the features of these variousaspects.

The wastewater treatment control system means a system in whichtreatment control elements such as a wastewater treatment apparatus, ameasuring unit for controlling the apparatus, a transmitting means ofmeasured data, a computing unit for establishing conditions from themeasured data and a control unit for controlling treatment conditionsfrom computed results are linked in such a form that they organicallyfunction. The invention relates to the system having the above-mentionedconstitution and features, and the system elements (treatment controlelements) thereof. Details thereof will become apparent from thefollowing description.

The wastewater for which the wastewater treatment control system of theinvention is intended is wastewater containing a hardly biodegradablecompound, and the invention is characterized by that the hardlybiodegradable compound can be degraded and removed at low cost. At thesame time, the invention is further characterized by that the BOD valueof wastewater containing a biodegradable material together with thehardly biodegradable compound can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an outline of a central controlsystem.

FIG. 2 is a block diagram showing an outline of a wastewater treatmentapparatus having a treatment tank for treating wastewater.

FIG. 3 is a block diagram showing an outline of a wastewater treatmentapparatus having a treatment tank for treating wastewater.

FIG. 4 is a block diagram showing the whole of the central controlsystem embodying the invention.

FIG. 5 is a block diagram showing the functional constitution of acentral control device 20.

FIG. 6 is a block diagram showing the functional constitution of acentral control device 20.

FIG. 7 shows one example of a data format of a measured value data base534.

FIG. 8 shows one example of a data format of a measured value data base534. FIG. 8A shows a data format for a COD value, and FIG. 8B shows adata format for a BOD value.

FIG. 9 shows one example of a data format of an image data base 532.

FIG. 10 shows one example of a data format of a predetermined value database 536.

FIG. 11 shows one example of a data format of a predetermined value database 536.

FIG. 12 is a block diagram showing the functional constitution of afactory terminal 30.

FIG. 13 is a block diagram showing the functional constitution of afactory terminal 30.

FIG. 14 is a schematic view showing a treatment tank connected to thefactory terminal 30.

FIG. 15 is a schematic view showing a treatment tank connected to thefactory terminal 30.

FIG. 16 is a block diagram showing the hardware constitution of thecentral control device 20.

FIG. 17 is a block diagram showing the hardware constitution of thefactory terminal 30.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

-   -   10: Wastewater Treatment Apparatus    -   20: Central Control Device    -   30: Factory Terminal    -   40: Factory    -   110: First COD-Measuring Unit    -   111: First BOD-Measuring Unit    -   200: First Section of Treatment Tank    -   210: Adding Unit    -   220: pH-Adjusting Unit    -   230: Stirring Unit    -   240: Filter    -   250: Second COD-Measuring Unit    -   251: Second BOD-Measuring Unit    -   300: Second Section of Treatment Tank    -   310: Adding Unit    -   320: pH-Adjusting Unit    -   330: Stirring Unit    -   340: Filter    -   350: Third COD-Measuring Unit    -   351: Third BOD-Measuring Unit    -   450: Drain Pump    -   460: Wastewater Control Tank    -   500: Receiving Unit    -   502: Output Unit    -   504: Totaling Unit    -   506: Photographed Image-Obtaining Unit    -   508: pH Value-Obtaining Unit    -   510: Judging Unit    -   512: COD-Obtaining Unit    -   513: BOD-Obtaining Unit    -   514: Computing Unit    -   516: Comparison Unit    -   518: Processing Unit    -   520: Input Unit    -   532: Image Data Base    -   534: Measured Value Data Base    -   536: Predetermined Value Data Base    -   600: COD-Measuring Unit    -   601: BOD-Measuring Unit    -   602: pH-Measuring Unit    -   604: Imaging Unit    -   606: Adding Unit I    -   607: Adding Unit II    -   608: pH-Adjusting Unit    -   610: Display Unit    -   612: Transmitting Unit    -   614: Receiving Unit    -   616: Processing Unit    -   712: Floppy Disk Drive    -   714: Floppy Disk    -   716: CD-ROM Drive    -   718: CD-ROM    -   812: Floppy Disk Drive    -   814: Floppy Disk    -   816: CD-ROM Drive    -   818: CD-ROM

DETAILED DESCRIPTION OF THE INVENTION

While the invention will be described below with reference toembodiments thereof, it is to be understood that the followingdescription is for illustrative purpose only and does not limit thescope of the invention.

Further, in the invention relating to wastewater treatment using theactivated sludge tank, the degradation of the hardly biodegradablecompound with the microorganism is conducted, together withbiodegradation with activated sludge, in the activated sludge tank.Accordingly, the activated sludge tank is also called a wastewatertreatment tank or simply a treatment tank. However, these tanks mean thesame one.

The hardly biodegradable compound to be degraded and removed fromwastewater by an embodiment of the invention, that is to say, thespecific compound, means a compound that is hardly degraded withconventional activated sludge, for example a compound having abiodegradation rate of 50% when a degradation test is conducted by theMITI method. Above all, the wastewater treatment control system of theinvention is particularly effective in removing a compound having abiodegradation rate as low as 25% or less, further 15% or less or stillfurther 10% or less measured by the above-mentioned test method.

The hardly degradable compound-containing wastewater for which anembodiment of the invention is intended means wastewater containing thespecific compound at such a concentration level that the wastewatercannot be discharged as it is. Specific examples thereof includeindustrial soap-containing wastewater containing the specific compoundin an amount exceeding a regulated COD value, photographicprocessing-related wastewater containing an organic aminocarboxylic acidsuch as EDTA (ethylenediaminetetraacetic acid), DTPA(diethylenetriaminepentaacetic acid) or PDTA(1,3-propanediaminetetraacetic acid), hardly biodegradable chelatingagent-containing wastewater discharged from facilities of the pulpindustry or the plating industry, particularly, electroless platingwastewater, surfactant-containing wastewater discharged from facilitieshandling detergents for industrial use or domestic use containing nonylphenol surfactants, organic chlorine compound (solvent)-containingwastewater discharged from facilities of the electric industry or themachinery industry, organic solvent-containing wastewater dischargedfrom organic chemical factories and washing wastewater of the foodindustry. However, the wastewater for which the invention is intended isnot limited thereto, and may be any as long as it contains the hardlybiodegradable organic compound, that is to say, the specific compound,at such a level that it can not be directly discharged.

Although the COD value of wastewater of this type exceeds an effluentcontrol level in an area in question, it extends from 20 ppm to tens ofthousands of parts per million in many cases, and from about 100 ppm toabout 1000 ppm in more cases.

It is possible to determine the concentration of the specific compounditself by various analysis methods including liquid chromatography.However, the characteristic value corresponding to the concentration ofthe specific compound is a characteristic value that can be used inplace of the concentration. For example, it is the COD value at the timewhen the COD value acts for the concentration. As the alternativecharacteristic value, the COD value is most preferred in that it can bedetermined by automatic analysis for a short period of time. When theCOD value is used as the alternative characteristic value, any ofCOD.sub.Mn, COD.sub.OH and COD.sub.Cr specified in JIS K0102 (FactoryEffluent Test Method), sections 17, 19 and 20 may be used as the COD, aslong as any of them or a characteristic corresponding thereto isselected, or as long as one is selected in one wastewater treatmentcontrol system.

Devices for measuring the COD value include but are not limited to, forexample, commercially available devices such as OD-1000/1100manufactured by COS, CODA-211/212 manufactured by HORIBA and a Hiranumafully automatic COD measuring device, COD-1500, manufactured by HitachiHigh Technologies Co., Ltd. Any one may be used as long as it is adevice with which the COD value can be measured.

The BOD value is basically measured on the basis of a BOD measuringmethod specified in JIS K0102 (Factory Effluent Test Method), section21. However, this is unsuitable and impractical for steadily proceedingwith the wastewater treatment control in many cases, in terms of timeand labor required for the measurement of the BOD.sub.5 value. It istherefore rather actual to employ the dissolved oxygen concentration(DO) or the compacted BOD value such as the BOD.sub.1 value, for whichthe relationship with the BOD5 is grasped for each type of wastewater.Dissolved oxygen concentration (DO) measuring devices are used as simpleBOD meters, which include, for example, an ICH automatic DO measuringdevice manufactured by Core Chushikoku Company and an automatic BODmeasuring device manufactured by Nippon Kankyo Gijutsu Co. Ltd. All ofthese devices rapidly determine the dissolved oxygen concentration asthe alternative characteristic value of the BOD by electrolysis.

Further, data on the first day in the measurement of the BOD.sub.5 inaccordance with JIS K0102 may be utilized as the BOD.sub.1. Measuringdevices available in that case include, for example, a five-day workweek-correspondence type BOD measuring device manufactured by NipponKankyo Gijutsu Co. Ltd.

Also when these alternative characteristic values of the BOD.sub.5 areused, it is to be understood that measured values thereof are called theBOD value.

It is preferred that the measurement of the concentration, the COD andBOD values of the specific compound or the alternative characteristicvalue thereof is made at both of an inlet and an outlet of eachactivated sludge tank. In the case of a two-tank type activated sludgetank, the measurement is desirably made at three positions, an inlet ofa first tank, an outlet of the first tank (the same as an inlet of asecond tank) and an outlet of the second tank. The method of conductingthe treatment in a plurality of treatment tanks is a preferredembodiment, because the microorganism can be easily optimized, resultingin space savings and short-time degradation treatment. Above all, thetwo-tank type treatment tank is preferred.

The microorganism that can degrade the above-mentioned specificcompound, that is to say, the specific microorganism will be describedbelow. As to the specific microorganism, for each specific compound,there is a specific degrading bacterium that can degrade it, and thereis a combination of a certain specific compound and the specificmicroorganism compatible with the specific compound.

For example, when the specific compounds are aromatic hydrocarboncompounds (for example, a phenol), organic solvents (for example,toluene and trichloroethylene) or organic chlorine compounds (forexample, dioxin and PCB), bacteria belonging to Pseudomonas andmicroorganisms belonging to Methylosinus, Methylomonas,Methylobacterium, Hethylocystis, Alcaligenes, Mycobacterium,Nitrosomonas, Xanthomonas, Spirillum, Vibrio, Bacterium, Achromobacter,Acinetobacter, Flavobacterium, Chromobacterium, Desulfovibrio,Desulfotomaculum, Micrococcus, Sarcina, Bacillus, Streptomyces,Nocardia, Corynebacterium, Pseudobacterium, Arthrobacter,Brevibacterium, Saccharomyces and Lactobacillus, which can degrade them,can be used as the specific microorganisms.

As for the specific microorganisms having ability to degrade metalchelating agents such as EDTA and heavy metal chelates in which themetal chelating agents are attached to heavy metals by complex bonding,bacteria belonging to Bacillus include Bacillus editabidus, Bacillussubtilis, Bacillus megaterium and Bacillus sphaericus. These are easilyavailable, for example, as Bacillus editabidus-1 (National Institute ofAdvanced Industrial Science and Technology, FERM P-13449), Bacillussubstilis NRIC 0068, B. megaterium NRIC 1009 and B. sphaericus NRIC1013.

Different specific microorganisms having ability to degrade EDTA includePseudomonas and Alcaligenes described in JP-A-5843782 (the term “JP-A”as used herein means an “unexamined published Japanese patentapplication”), bacterial strains of Agrobacterium described in Appliedand Environmental Microbiology, 56, 3346-3353 (1990) and Gram-negativeisolates described in Applied and Environmental Microbiology, 58, No. 2,671-676 (February, 1992). Of these, for example, Pseudomonas editabidusis available as Pseudomonas editabidus-1 (FERM P-13634).

Still different microorganisms having activity to degrade EDTA includeBacillus editabidus and Mesophilobacter editabidus that are marinebacteria. This organic aminocarboxylic acid-degrading bacterium,Bacillus editabidus, is a strain to which Bacillus editabidus-M1 (FERMP-14868) and Bacillus editabidus-M2 (FERM P-14869) belong. Further, theorganic aminocarboxylic acid-degrading bacterium, Mesophilobactereditabidus, is a strain to which Mesophilobacter editabidus-M3 (FERMP-14870) belongs.

Surfactant-degrading bacteria include, for example, Pseudomonasfluorescence 3p (atcc31483) described in U.S. Pat. No. 4,274,954. Thewastewater to which these microorganisms are to be applied is, forexample, wastewater containing an anionic, nonionic or cationicsurfactant, especially wastewater containing a poorly biodegradablesurfactant called a so-called hard surfactant, above all, wastewatercontaining a sulfonic acid group-containing surfactant.

Microorganisms that degrade phenols or cresol compounds include, forexample, Pseudomonas putida cb-173 (atcc31800) described in U.S. Pat.Nos. 4,352,886 and 4,556,638. The wastewater to which thesemicroorganisms are to be applied is, for example, wastewater from phenolresin factories, wastewater from cresol resin factories, wastewater fromfactories of polyphenols obtained from bisphenol A or the like, andphenol-containing wastewater discharged from plate-making processes orphotoresist formation processes in which these phenolic resins areemployed.

As for the specific microorganism to be added, in addition to theabove-mentioned microorganism already isolated, one newly screened fromsoil depending on the purpose can also be utilized. A mixed system of aplurality of strains may also be used. In the case of the microorganismseparated by screening, it may be one unidentified.

When the wastewater treatment tank has a plurality of activated sludgetanks, the specific microorganism is preferably added to a second tankor later. Further, when the wastewater treatment tank has one activatedsludge tank, it is a preferred embodiment that the specificmicroorganism is added to a latter part of a flow path. However, anembodiment of adding the specific microorganism to a beginning part ofthe treatment tank is not excluded.

The amount of the microorganism added is from 100 g to 50 kg, andpreferably from 500 g to 5,000 g, per cubic meter of wastewater, by thedry weight of the microorganism. In this embodiment, the microorganismmay be added either directly or in a state where the microorganism isimmobilized on a carrier. The term “carrier” as used herein means amedium for fixing the microorganism, and it is, for example, activatedcarbon particles, carbon fiber or a polymer gel. The use of the carrieris a more preferred embodiment because of enhanced activity of themicroorganism. Further, in place of the microorganism, a splittingenzyme contained in the microorganism may be added.

As methods for comprehensively immobilizing the microorganism, variousknown methods can be used. Most generally, the methods include a methodof immobilizing a microorganism in an aqueous gel of a synthetic polymer(described in JP-A-10-263575). A method of immobilizing a microorganismon activated carbon particles (described in JP-A-11-77074) and a methodof immobilizing a microorganism on a carbon fiber cloth (described inJP-A-11-207379) may also be used.

The volume of the treatment tank for treating the wastewater variesdepending on the amount of the wastewater. For example, the residencetime of the wastewater in the treatment tank is adjusted to about 0.2day to about 20 days. In particular, it is preferred that the residencetime of the wastewater in the treatment tank is adjusted to about 0.5day to about 5 days. The plurality of treatment tanks may be installed.The installation of the plurality of treatment tanks makes it possibleto treat the wastewater more efficiently in small space for a shortperiod of time.

When degrading ability of the specific microorganism in the wastewatertreatment tank is lowered, or when biodegrading ability is lowered, anutrient source (also referred to as a nutriment) for the specificmicroorganism or for the microorganism in activated sludge is suppliedto the treatment tank. In this case, the nutrient source for thespecific microorganism and that for the microorganism inactivated sludgeare common in many cases. Further, instead of supplying the nutrientsource, the amount of the specific microorganism added may be increased,or the amount of activated sludge returned maybe increased. Depending ona state of degradation behavior of the treatment tank, it is decidedwhich is employed, the supply of the nutrient source or the increase inthe amount of the microorganism.

When degrading ability of the specific microorganism is lowered, thenutrient source for the specific microorganism is added to the treatmenttank, preferably to the latter part of the flow path of the treatmenttank. Particularly, an organic nutrient source giving a nutrient sourcesuitable for growth of the specific microorganism, and/or a nutrientsource comprising an inorganic salt is added to the treatment tank.Examples of the organic nutrient sources added include polypeptones,yeast extract, meat extract and molasses. Examples of the inorganicnutrient sources added include various types of phosphates and magnesiumsalts. For example, the organic nutrient source is added in an amount of0.001 to 5% by weight, and the inorganic nutrient source is added in anamount of 0.1 to 1% by weight based on the organic nutrient source. Morepreferably, the organic nutrient source is added in an amount of 0.01 to1% by weight, and the inorganic nutrient source is added in an amount of0.1 to 1% by weight based on the organic nutrient source.

Further, in the wastewater treatment apparatus, the specificmicroorganism itself may be added in place of the nutrient source. Thetype of specific microorganism added herein is similar to that of thespecific microorganism preliminarily added, so that the explanationthereof is omitted. Furthermore, in the wastewater treatment apparatus,the specific microorganism may be added in a state where the specificmicroorganism is immobilized on a carrier, or directly withoutimmobilization thereof on a carrier.

On the other hand, when activity (biodegradability) of the activatedsludge (not the specific microorganism) is lowered, the nutrient sourcefor the microorganism in the activated sludge is supplied to thetreatment tank (preferably, to the first tank when the plurality oftreatment tank are used, and to a foremost part of a flow path, when thetank has the flow path). Specifically, the nutrient sources for themicroorganisms in the activated sludge are the same as theabove-mentioned nutrient sources for the specific microorganisms. Inplace of addition of the nutrient source, the amount of sludge returnedmay be increased. Further, both the nutrient source and the sludgemicroorganism may also be supplied.

In the wastewater treatment apparatus as used herein, sludge containinga microorganism having biodegradability is added to the treatment tankin an amount of 10 g to 50 kg, and more preferably in an amount of 20 gto 5000 g, per cubic meter of wastewater, by the dry weight.

In the wastewater treatment apparatus, the nutrient source, the sludgeor the specific microorganism is added with stirring a solution in thetreatment tank. For example, when the nutrient source or themicroorganism is a liquid, it is added from a solution tank or acontainer through a solution supply pump or by hand while stirring thesolution in the treatment tank by aeration or with a stirrer. When thenutrient source or the microorganism is a solid such as a powder, it isintroduced into the treatment tank through an introduction hopper or aconveying instrument. The microorganism or the nutrient source is moreuniformly dispersed in the solution in the treatment tank by adding themicroorganism or the nutrient source while stirring the solution in thetank.

Further, in the wastewater treatment apparatus, both the nutrient sourceand the microorganism may be added to the treatment tank. In a mostpreferred embodiment, changes in COD value are confirmed for severaldays after addition of the nutrient source, and when the degree oflowered activity of the microorganism is not recovered, themicroorganism is added. At this time, when further addition of themicroorganism does not recover the degree of lowered COD value, thewastewater may be diluted. This allows the wastewater treatmentapparatus to discharge the wastewater surely decreased in COD value.

Wastewater treatment business in which wastewater containing such hardlybiodegradable materials is treated with microorganisms includes a methodof selling the microorganisms to users conducting wastewater treatment.However, when the microorganisms are proliferated, once the users buythe microorganisms, additional buying becomes unnecessary. It istherefore difficult to continue the business of selling themicroorganisms, resulting in infeasibility of the business. Further,professional control of the microorganisms in the treatment tanksbecomes necessary, so that it is preferred that control service isadded.

To the users, merits of introducing this system are merely a reductionin the amount of diluent water that has previously been used (costreduction due to water savings) and reduction of cost that haspreviously been required for recovery and incineration. It is thereforepreferable to get a reward obtained by multiplying the cost reduced thanbefore by a specific rate, in compensation for the introduction of thissystem. In particular, it is more preferable to get a reward obtained bymultiplying the cost reduction due to water savings by a specific rate.

For the meantime, in the degradation treatment method using themicroorganism, the efficiency thereof inevitably fluctuates depending onenvironmental conditions (such as atmospheric temperature, watertemperature and wastewater concentration). According to this accountingmethod, even in the unlikely event that this system is not activated atall for some reason, the treatment of wastewater is possible by dilutionor recovery incineration in the same manner as before the introductionof this system. In such a state, therefore, the cost charged by theusers becomes zero (the same as the state before the introduction), andthe risk of the users involved in the introduction of this system goesaway.

The invention will be illustrated below with reference to embodiments,but it is to be understood that the following embodiments do not limitthe scope of the invention. All combinations of features illustrated inthe embodiments are not necessarily indispensable to means for solvingthe problems.

FIG. 1 is a block diagram showing an outline of a central controlsystem. A factory 40 periodically measures the COD and/or BOD values ofwastewater before and after treatment and the pH value of a solution ina treatment tank for treating the wastewater, and transmits them to acentral control device 20. Here, the factory 40 may measure watertemperature, an image, TOC, the date of measurement and the like, inaddition to the COD and/or BOD values, and the pH value. Further, it maytake a photograph of a state of the treatment tank with a photographingdevice such as a digital camera, and periodically transmit image data tothe central control device 20.

In particular, the factory 40 transmits both the COD and/or BOD valuesbefore treatment of the wastewater and the COD and/or BOD values aftertreatment to the central control device 20.

The term “factory” as used herein means a wastewater treatment plant,which includes an urban sewage-treatment plant, a wastewater treatmentplant of a large-scale facility and a terminal treatment plant of amanufacturing facility.

An operator 22 confirms data received from the factory 40 by the centralcontrol system 20, and judges whether the operator makes contact withthe factory 40 or not. When the operator 22 makes contact with thefactory 40, the operator may enter to the central control device 20information indicating an instruction to the factory 40, or may directlymake contact with the factory 40 by telephone without entering theinformation in the central control device 20.

For example, the central control device 20 may directly control the pHof the solution in the treatment tank by automatic addition of an acidor an alkali according to the input of the operator 22, or may transmitto the factory 40 the pH value of the solution in the treatment tank,information indicating the amount of an acid or an alkali to be added,or instruction information indicating that the pH is to be controlled.Further, the central control device 20 may automatically add thenutrient source for the microorganism.

FIG. 2 is a block diagram showing an outline of a wastewater treatmentapparatus. The wastewater treatment apparatus comprises a factoryterminal 30, a treatment tank and incidental equipment of the treatmenttank. The factory terminal 30 transmits instruction information to theincidental equipment of the treatment tank or receives measurementinformation from the incidental equipment to control the treatment tank.The wastewater treatment apparatus according to an embodiment of theinvention degrades the hardly biodegradable material contained in thewastewater with the microorganism to reduce the COD concentration of thewastewater. Specifically, the wastewater treatment apparatus generallycuts the COD value of the wastewater having a COD value of 200 ppm tothousands of parts per million in half to about 100 ppm.

FIG. 3 is a block diagram showing an outline of a wastewater treatmentapparatus. The wastewater treatment apparatus comprises a factoryterminal 30, a treatment tank and incidental equipment of the treatmenttank. The factory terminal 30 transmits instruction information to theincidental equipment of the treatment tank or receives measurementinformation from the incidental equipment to control the treatment tank.The wastewater treatment apparatus according to an embodiment of theinvention degrades the hardly biodegradable material contained in thewastewater with the microorganism to reduce the COD concentration of thewastewater. Specifically, the wastewater treatment apparatus generallycuts the COD value of the wastewater having a COD value of 200 ppm tothousands of parts per million in half to about 100 ppm, thus satisfyinga control level in an area in question.

At the same time, the wastewater treatment apparatus degrades a materialresponsible for the BOD value contained in the wastewater by activatedsludge. Specifically, the wastewater treatment apparatus reduces the BODvalue of the wastewater generally having a BOD value of 200 ppm tothousands of parts per million to an effluent standard (in many cases,160 ppm or less) or lower, or a control value of a sewage effluentstandard (in many cases, from 300 to 600 ppm or less) or lower, in anarea in question.

FIG. 5 is a block diagram showing the functional constitution of thecentral control device 20. The central control device 20 has a receivingunit 500, an output unit 502, a totaling unit 504, a photographedimage-obtaining unit 506, a pH value-obtaining unit 508, a judging unit510, a COD-obtaining unit 512, a computing unit 514, a comparison unit516, a processing unit 518, an input unit 520, an image data base 532, ameasured value data base 534 and a predetermined value data base 536.

The image data base 532 stores image data of an image obtained byphotographing a state of the treatment tank 90, in a state where thedata is matched to microorganism ID identifying a microorganism. Themeasured value data base 534 stores a COD concentration of thewastewater before treatment and a COD concentration of the wastewaterafter treatment in a state where the values are coordinated to themicroorganism ID and a factory number. The predetermined value data base536 stores a COD predetermined value that is a value preliminarilydetermined with respect to a COD concentration, and a pH predeterminedvalue that is a value preliminarily determined with respect to a pHvalue. As the pH predetermined value, a value within the range centeredat a pH value suitable for a microorganism is stored.

The receiving unit 500 receives the factory number identifying thefactory 40, the image data, the pH value and the COD concentrations fromthe factory terminal 30 for each treatment tank. Here, the receivingunit 500 receives the COD concentration of the wastewater beforetreatment and the COD concentration of the wastewater after treatment asCOD concentrations. The receiving unit 500 transmits the image data andthe factory number received to the photographed image-obtaining unit506. Further, the receiving unit 500 transmits the pH value and thefactory number received to the pH value-obtaining unit 508. Furthermore,the receiving unit 500 transmits the COD concentrations and the factorynumber to the COD-obtaining unit 512.

The photographed image-obtaining unit 506 stores the received image datain the image data base 532 in a state where the data is matched to thefactory number. The pH value-obtaining unit 508 stores the received pHvalue in the measured value data base 534 in a state where the value ismatched to the factory number. Further, the pH value-obtaining unit 508transmits the received pH value and the factory number to the judgingunit 510. The COD-obtaining unit 512 stores the received COD values inthe measured value data base 534 in a state where the values are matchedto the factory number. Further, the COD-obtaining unit 512 transmits thereceived COD values and the factory number to the computing unit 514.

The judging unit 510 extracts the microorganism ID from the measuredvalue data base 534, the microorganism ID being stored in a state wherethe ID is matched to the factory number received from the pHvalue-obtaining unit 508. The microorganism ID is one example ofmicroorganism-specifying information specifying a microorganism. Then,the judging unit 510 extracts the pH predetermined value from thepredetermined value data base 536, the pH predetermined value beingstored in a state where the value is matched to the microorganism ID.Then, the judging unit 510 judges whether the pH value received from thepH value-obtaining unit 508 is included in the pH predetermined valueextracted from the predetermined value data base 536 or not. When thejudging unit 510 judges that the pH value received from the pHvalue-obtaining unit 508 is not included in the pH predetermined valueextracted from the predetermined value data base 536, the judging unittransmits the pH predetermined value, the pH value received from the pHvalue-obtaining unit 508 and the factory number to the processing unit518.

The processing unit 518 calculates a pH difference by subtracting anintermediate value of the pH predetermined values received from thejudging unit 510, from the pH value. The processing unit 518 transmitsan instruction to add an acid to the treatment tank 90, when the pHdifference calculated is a positive number, and an instruction to add analkali to the treatment tank 90, when the pH difference calculated is anegative number, together with the pH difference, to the factoryterminal 30 specified by the factory number.

The computing unit 514 receives the COD concentrations and the factorynumber from the COD-obtaining unit 512. The computing unit 514 subtractsthe COD concentration after treatment from the COD concentration beforetreatment to calculate a COD difference. The computing unit 514 storesthe calculated COD difference in the measured value data base 534 in astate where the difference is matched to the factory number. Further,the computing unit 514 transmits the calculated COD difference and thefactory number to the comparison unit 516.

The comparison unit 516 extracts the microorganism ID from the measuredvalue data base 534, the microorganism ID being stored in a state wherethe ID is matched to the factory number received. Then, the comparisonunit 516 extracts the COD predetermined value stored in a state wherethe values are coordinated to the microorganism ID extracted. Then, thecomparison unit 516 compares the extracted COD predetermined value withthe COD difference received from the computing unit 514. When the CODdifference is judged to be less than the COD predetermined value, thecomparison unit 516 transmits less-than-predetermined-value informationindicating that the COD difference is less than the COD predeterminedvalue, together with the COD difference and the factory number, to theprocessing unit 518. The processing unit 518 transmits the receivedless-than-predetermined-value information and the COD difference to thefactory terminal 30 specified by the factory number.

The totaling unit 504 summarizes the measured values stored in themeasured value data base 534 for each microorganism ID. Specifically,the totaling unit 504 extracts the COD difference for each microorganismID, and calculates an average value. Further, the totaling unit 504 mayintegrate the COD difference for each microorganism ID. Furthermore, thetotaling unit 504 may calculate the rate of change in the CODdifference. Thus, the totaling unit 504 totals the measured valuesstored in the measured value data base 534, and transmits resultsthereof to the output unit 502.

The output unit 502 outputs the results of totaling received from thetotaling unit 504. Further, the output unit 502 extracts the image datafrom the image data base 532, and displays it. The operator of thecentral control device 20 inspects an image displayed. When anabnormality is discovered in the image displayed, the operator entersabnormality information indicating the abnormality and the factorynumber in the input unit 520. When the input unit 520 accepts theabnormality information, it transmits the factory number and theabnormality information to the processing unit 518. The processing unit518 transmits the received abnormality information to the factoryterminal 30 specified by the factory number.

FIG. 6 is a block diagram showing the whole of the central controlsystem embodying the invention. This central control system comprises acommunication network 10, the central control device 20, the factoryterminals 30 and treatment tanks 90. The factory terminals 30 are eachplaced in factories 40 physically apart from one another. The factoryterminals 30 are each connected to the treatment tanks 90, obtainwastewater information such as the measured values of COD and BOD, andtransmit it to the central control device 20.

The central control device 20 receives the wastewater information fromthe factory terminals 30 through the communication network 10, andstores it in a database. Further, the central control system 20transmits treatment information indicating treatment to be conducted bythe factories 40 to the factory terminals 30, on the basis of thewastewater information received. The communication network 10 is a cablecommunication network, a wireless communication network or anycombination thereof, and includes an internet, a PSTN (public switchedtelephone network), a LAN and a WAN.

FIG. 6 is a block diagram showing the functional constitution of thecentral control device 20. The central control device 20 has a receivingunit 500, an output unit 502, a totaling unit 504, a photographedimage-obtaining unit 506, a pH value-obtaining unit 508, a judging unit510, a COD-obtaining unit 512, a BOD-obtaining unit 513, a computingunit 514, a comparison unit 516, a processing unit 518, an input unit520, an image data base 532, a measured value data base 534 and apredetermined value data base 536.

The image data base 532 stores image data of an image obtained byphotographing a state of the treatment tank 90, in a state where thedata is matched to microorganism ID identifying a microorganism. Themicroorganism ID specifies a microorganism or wastewater used in thefactory, and is the type of microorganism, the lot of culture orinformation corresponding thereto. The measured value data base 534stores COD and BOD values of the wastewater before treatment and COD andBOD values of the wastewater after treatment in a state where the valuesare matched to the microorganism ID and a factory number. Thepredetermined value data base 536 stores a COD predetermined value thatis a value preliminarily determined with respect to a COD value, a BODpredetermined value that is a value preliminarily determined withrespect to a BOD value, and a pH predetermined value that is a valuepreliminarily determined with respect to a pH value. As the pHpredetermined value, a value within the range centered at a pH valuesuitable for a microorganism is stored.

The receiving unit 500 receives the factory number identifying thefactory 40, the image data, the pH value, the BOD values and the CODvalues from the factory terminal 30 for each treatment tank. Here, thereceiving unit 500 receives the COD and BOD values of the wastewaterbefore treatment, and COD and BOD values of the wastewater aftertreatment as COD and BOD values. The receiving unit 500 transmits theimage data and the factory number received to the photographedimage-obtaining unit 506. Further, the receiving unit 500 transmits thepH value and the factory number received to the pH value-obtaining unit508. Furthermore, the receiving unit 500 transmits the COD values, theBOD values and the factory number to the COD-obtaining unit 512 and theBOD-obtaining unit 513.

The photographed image-obtaining unit 506 stores the received image datain the image data base 532 in a state where the data is matched to thefactory number. The pH value-obtaining unit 508 stores the received pHvalue in the measured value data base 534 in a state where the value ismatched to the factory number. Further, the pH value-obtaining unit 508transmits the received pH value and the factory number to the judgingunit 510. The COD-obtaining unit 512 stores the received COD values inthe measured value data base 534 in a state where the values are matchedto the factory number. Further, the COD-obtaining unit 512 transmits thereceived COD values and the factory number to the computing unit 514.The BOD-obtaining unit 513 stores the received BOD values in themeasured value data base 534 in a state where the values are matched tothe factory number. Further, the BOD-obtaining unit 512 transmits thereceived BOD values and the factory number to the computing unit 514.

The judging unit 510 extracts the microorganism ID from the measuredvalue data base 534, the microorganism ID being stored in a state wherethe ID is matched to the factory number received from the pHvalue-obtaining unit 508. The microorganism ID is one ofmicroorganism-specifying information specifying a microorganism. Then,the judging unit 510 extracts the pH predetermined value from thepredetermined value data base 536, the pH predetermined value beingstored in a state where the value is matched to the microorganism ID.Then, the judging unit 510 judges whether the pH value received from thepH value-obtaining unit 508 is included in the pH predetermined valueextracted from the predetermined value data base 536 or not. When thejudging unit 510 judges that the pH value received from the pHvalue-obtaining unit 508 is not included in the pH predetermined valueextracted from the predetermined value data base 536, the judging unittransmits the pH predetermined value, the pH value received from the pHvalue-obtaining unit 508 and the factory number to the processing unit518.

The processing unit 518 calculates a pH difference by subtracting anintermediate value of the pH predetermined values received from thejudging unit 510, from the pH value. The processing unit 518 transmitsan instruction to add an acid to the treatment tank 90, when the pHdifference calculated is a positive number, and an instruction to add analkali to the treatment tank 90, when the pH difference calculated is anegative number, together with the pH difference, to the factoryterminal 30 specified by the factory number.

The computing unit 514 receives the COD values and the factory numberfrom the COD-obtaining unit 512, and the BOD values and the factorynumber from the BOD-obtaining unit 513. The computing unit 514 subtractsthe COD value after treatment from the COD value before treatment tocalculate a COD difference, and subtracts the BOD value after treatmentfrom the BOD value before treatment to calculate a BOD difference. Thecomputing unit 514 stores the calculated COD and BOD differences in themeasured value data base 534 in a state where the differences arematched to the factory number. Further, the computing unit 514 transmitsthe calculated COD and BOD differences and the factory number to thecomparison unit 516.

The comparison unit 516 extracts the microorganism ID from the measuredvalue data base 534, the microorganism ID being stored in a state wherethe ID is matched to the factory number received. Then, the comparisonunit 516 extracts the COD predetermined value and the BOD predeterminedvalue stored in a state where the values are matched to themicroorganism ID extracted. Then, the comparison unit 516 compares theextracted COD predetermined value and BOD predetermined value with theCOD difference and BOD difference, respectively, which are received fromthe computing unit 514. When the COD difference is judged to be lessthan the COD predetermined value, the comparison unit 516 transmitsless-than-predetermined-value information indicating that the CODdifference is less than the COD predetermined value, together with theCOD difference and the factory number, to the processing unit 518.Similarly, when the BOD difference is judged to be less than the BODpredetermined value, the comparison unit 516 transmitsless-than-predetermined-value information indicating that the BODdifference is less than the BOD predetermined value, together with theBOD difference and the factory number, to the processing unit 518. Theprocessing unit 518 transmits the received less-than-predetermined-valueinformation, the COD difference and the BOD difference to the factoryterminal 30 specified by the factory number.

The totaling unit 504 summarizes the measured values stored in themeasured value data base 534 for each microorganism ID. Specifically,the totaling unit 504 extracts the COD difference and the BOD differencefor each microorganism ID, and calculates each average value. Further,the totaling unit 504 may integrate the COD difference and the BODdifference for each microorganism ID. Furthermore, the totaling unit 504may calculate the rate of change in each of the COD difference and theBOD difference. Thus, the totaling unit 504 totals the measured valuesstored in the measured value data base 534, and transmits resultsthereof to the output unit 502.

The output unit 502 outputs the results of totaling received from thetotaling unit 504. Further, the output unit 502 extracts the image datafrom the image data base 532, and displays it. The operator of thecentral control device 20 inspects an image displayed. When anabnormality is discovered in the image displayed, the operator entersabnormality information indicating the abnormality and the factorynumber in the input unit 520. When the input unit 520 accepts theabnormality information, it transmits the factory number and theabnormality information to the processing unit 518. The processing unit518 transmits the received abnormality information to the factoryterminal 30 specified by the factory number.

FIG. 7 shows one example of a data format of the measured value database 534. The measured value data base 534 has a table and amicroorganism ID field for each factory number. The microorganism IDfield stores the microorganism ID for identifying the microorganism usedfor wastewater treatment in the factory. The microorganism ID may be,for example, information indicating the type of microorganism orinformation indicating the lot of culture.

The table has a field of the date and time, a field of treatment tank 1and a field of treatment tank 2. The field of the date and time storesinformation indicating the date and time. The fields of treatment tank 1and treatment tank 2 each include a field before treatment, a fieldafter treatment and a field of the difference. The field beforetreatment stores information indicating the COD concentration before thewastewater is treated with the microorganism in the treatment tank 90.The field after treatment stores information indicating the CODconcentration after the wastewater is treated with the microorganism inthe treatment tank 90. The field of the difference stores informationindicating the COD difference obtained by subtracting the CODconcentration after treatment from the COD concentration beforetreatment.

When the COD-obtaining unit 512 obtains the COD concentration beforetreatment and the COD concentration after treatment, it stores them inthe measured value data base 534 in a state where they are matched tothe date obtained. Further, the computing unit 514 stores the CODdifference calculated in a state where the difference is matched to thedate on which the COD concentrations have been obtained by theCOD-obtaining unit 512. Here, the measured value data base 534 storesthe microorganism ID for each factory number. However, instead of this,the microorganism ID may be stored for each treatment tank, as anotherexample.

FIG. 8 shows one example of a data format of the measured value database 534. The measured value data base 534 has a table of the COD valueor the BOD value and a microorganism ID field for each factory number.The microorganism ID field stores the microorganism ID for identifyingthe microorganism used for wastewater treatment in the factory. Themicroorganism ID may be, for example, information indicating the type ofmicroorganism or information indicating the lot of culture.

FIG. 8A shows an example of a data format for the COD value, and FIG. 8Bshows an example of a data format for the BOD value. Each of the tablesfor the COD value and the BOD value has, a field of the date and time, afield of treatment tank 1 and a field of treatment tank 2. The exampleshown in FIG. 8 is used for a two-tank type treatment tank, so that theformat has the fields of treatment tank 1 and treatment tank 2. Forexample, however, in the case of a one-tank type treatment tank, it goeswithout saying that the format has only the field of treatment tank 1.The field of the date and time stores information indicating the dateand time. The fields of treatment tank 1 and treatment tank 2 eachinclude a field before treatment, a field after treatment and a field ofthe difference. The field before treatment stores information indicatingthe COD and BOD values before the wastewater is treated with themicroorganism in the treatment tank 90. The field after treatment storesinformation indicating the COD and BOD values after the wastewater istreated with the microorganism in the treatment tank 90. The field ofthe difference stores information indicating the COD difference and BODdifference each obtained by subtracting the COD value and BOD valueafter treatment from the COD value and BOD value before treatment,respectively.

In this embodiment, the image data is also employed as one ofinformation for control. FIG. 9 shows one example of a data format ofthe image data base 532. The image data base 532 has a table and amicroorganism ID field for each factory number. The microorganism IDfield stores the microorganism ID for identifying the microorganism usedfor wastewater treatment in the factory.

The table contains a field of the date and time and an image field. Thefield of the date and time stores information indicating the date andtime. The image field stores the image data. Here, the image field maystore either the image data itself or information identifying the imagedata. The term “image data” as used herein means image data showing aphotographed image of the treatment tank 90, and data for monitoringthat can diagnose the state of wastewater treatment such as the state ofdiscoloration of the wastewater during treatment or the state of sludge.In the wastewater treatment control system of the invention, it ispreferable to collect also the image data. Thus, the photographedimage-obtaining unit (506 in FIG. 6) stores the image data in this imagedata base 532 in a state where the image data is matched to the date onwhich the image data is prepared.

FIG. 10 shows one example of a data format of the predetermined valuedata base 536. The predetermined value data base 536 contains amicroorganism ID field, a tank field, a COD predetermined value fieldand a pH predetermined value field. The microorganism ID field storesthe microorganism ID for identifying the microorganism. The tank fieldstores information identifying the tank. The COD predetermined valuefield stores information indicating the COD predetermined value. The pHpredetermined value field stores information indicating the pHpredetermined value.

FIG. 11 shows one example of a data format of the predetermined valuedata base 536. The predetermined value data base 536 contains amicroorganism ID field, a tank field, a COD predetermined value field, aBOD predetermined value field and a pH predetermined value field. Themicroorganism ID field stores the microorganism ID for identifying themicroorganism. The tank field stores information identifying the tank.The COD predetermined value field stores information indicating the CODpredetermined value. The BOD predetermined value field storesinformation indicating the BOD predetermined value. The pH predeterminedvalue field stores information indicating the pH predetermined value.

FIG. 12 is a block diagram showing the functional constitution of thefactory terminal 30. The factory terminal 30 has a COD-measuring unit600, a pH-measuring unit 602, an imaging unit 604, an adding unit 606, apH-adjusting unit 608, a display unit 610, a transmitting unit 612, areceiving unit 614, and a processing unit 616.

The COD-measuring unit 600 measures the COD concentration of thewastewater before treatment and the COD concentration of the wastewaterafter treatment, and transmits the measured COD concentrations to thetransmitting unit 612. The pH-measuring unit 602 measures the pH of asolution in the treatment tank 90 for treating the wastewater, andtransmits the measured pH value to the transmitting unit 612. Theimaging unit 604 photographs a state in the treatment tank 90, andtransmits the photographed image data to the transmitting unit 612.

The transmitting unit 612 transmits the COD concentrations received fromthe COD-measuring unit 600, the pH value received from the pH-measuringunit 602 and the image data received from the imaging unit 604 to thecentral control device 20 in a state where they are matched to thefactory number identifying the factory terminal 30.

The receiving unit 614 receives the instruction to add an acid to thetreatment tank 90 and the pH difference, the instruction to add analkali to the treatment tank 90 and the pH difference,less-than-predetermined-value information and information indicating theCOD difference or abnormality information from the central controldevice 20. Then, the receiving unit 614 transmits the receivedinformation to the processing unit 616.

When the processing unit 616 receives the instruction to add an acid tothe treatment tank 90 and the pH difference, the processing unit 616calculates the amount of the acid to be added to the treatment tank 90,on the basis of the pH difference received. The processing unit 616transmits quantitative information indicating the amount of the acidcalculated to the pH-adjusting unit 608. The pH-adjusting unit 608 addsthe acid to the treatment tank 90 in an amount specified by thequantitative information received.

When the processing unit 616 receives the instruction to add an alkalito the treatment tank 90 and the pH difference, the processing unitcalculates the amount of the alkali to be added to the treatment tank90, on the basis of the pH difference received. The processing unit 616transmits quantitative information indicating the amount of the alkalicalculated to the pH-adjusting unit 608. The pH-adjusting unit 608 addsthe alkali to the treatment tank 90 in an amount specified by thequantitative information received.

When the processing unit 616 receives the less-than-predetermined-valueinformation and information indicating the COD difference from thereceiving unit 614, the processing unit calculates the amount of thenutriment to be added to the treatment tank 90, on the basis of the CODdifference. The processing unit 616 transmits nutriment quantitativeinformation indicating the amount of the nutriment calculated to theadding unit 606. The adding unit 606 adds the nutriment to the treatmenttank 90 in an amount specified by the nutriment quantitative informationreceived from the processing unit 616.

The processing unit 616 transmits the abnormality information receivedfrom the receiving unit 614 to the display unit 610. The display unit610 displays that an abnormality occurred in the treatment tank, onreceiving the abnormality information.

FIG. 13 is a block diagram showing the functional constitution of thefactory terminal 30. The factory terminal 30 has a COD-measuring unit600, a BOD-measuring unit 601, a pH-measuring unit 602, an imaging unit604, an adding unit I 606 for conducting addition for COD correction, anadding unit II 607 for conducting addition for BOD correction, apH-adjusting unit 608, a display unit 610, a transmitting unit 612 and areceiving unit 614 and a processing unit 616.

The COD-measuring unit 600 measures the COD value of the wastewaterbefore treatment and the COD value of the wastewater after treatment,and transmits the measured COD values to the transmitting unit 612.

The BOD-measuring unit 601 measures the BOD value of the wastewaterbefore treatment and the BOD value of the wastewater after treatment,and transmits the measured BOD values to the transmitting unit 612.

The pH-measuring unit 602 measures the pH of a solution in the treatmenttank 90 for treating the wastewater, and transmits the measured pH valueto the transmitting unit 612. The imaging unit 604 photographs a statein the treatment tank 90, and transmits the photographed image data tothe transmitting unit 612.

The transmitting unit 612 transmits the COD values received from theCOD-measuring unit 600, the BOD values received from the BOD-measuringunit 601, the pH value received from the pH-measuring unit 602 and theimage data received from the imaging unit 604 to the central controldevice 20 in a state where they are matched to the factory numberidentifying the factory terminal 30.

The receiving unit 614 receives the instruction to add an acid or analkali to the treatment tank 90 and the pH difference, eachless-than-predetermined-value information for the COD value and the BODvalue, and information indicating each difference thereof, orabnormality information from the central control device 20. Then, thereceiving unit 614 transmits the received information to the processingunit 616.

When the processing unit 616 receives the instruction to add an acid tothe treatment tank 90 and the pH difference, the processing unitcalculates the amount of the acid to be added to the treatment tank 90,on the basis of the pH difference received. The processing unit 616transmits quantitative information indicating the amount of the acidcalculated to the pH-adjusting unit 608. The pH-adjusting unit 608 addsthe acid to the treatment tank 90 in an amount specified by thequantitative information received.

When the processing unit 616 receives the instruction to add an alkalito the treatment tank 90 and the pH difference, the processing unitcalculates the amount of the alkali to be added to the treatment tank90, on the basis of the pH difference received. The processing unit 616transmits quantitative information indicating the amount of the alkalicalculated to the pH-adjusting unit 608. The pH-adjusting unit 608 addsthe alkali to the treatment tank 90 in an amount specified by thequantitative information received.

When the processing unit 616 receives the less-than-predetermined-valueinformation for the COD value and information indicating the CODdifference from the receiving unit 614, the processing unit calculatesthe amount of the nutrient source for the specific microorganism to beadded to the treatment tank 90, on the basis of the COD difference. Theprocessing unit 616 transmits nutrient source quantitative informationindicating the amount of the nutrient source calculated to the addingunit I 606 for adding the nutrient source for the specificmicroorganism. The adding unit I 606 adds the nutrient source to thetreatment tank 90 in an amount specified by the nutrient sourcequantitative information received from the processing unit 616.

When the processing 616 receives the less-than-predetermined-valueinformation for the BOD value and information indicating the BODdifference from the receiving unit 614, the processing unit calculatesthe amount of the nutrient source for a biodegrading bacterium(microorganism in sludge) to be added to the treatment tank 90, on thebasis of the BOD difference. The processing unit 616 transmits nutrientsource quantitative information indicating the amount of the nutrientsource calculated to the adding unit II 607 for adding the nutrientsource for the biodegrading bacterium. The adding unit II 607 adds thenutrient source to the treatment tank 90 in an amount specified by thenutrient source quantitative information received from the processingunit 616.

The processing unit 616 transmits the abnormality information receivedfrom the receiving unit 614 to the display unit 610. The display unit610 displays that an abnormality occurred in the treatment tank, onreceiving the abnormality information.

FIG. 14 is a schematic view showing the treatment tank 90 connected tothe factory terminal 30. In this embodiment, an explanation is givenusing the treatment tank in which two tanks are arranged in series, asone example. The treatment tank 90 comprises a control tank 100, a firstCOD-measuring unit 110, a first treatment tank 200, a secondCOD-measuring unit 250, a second treatment tank 300, a thirdCOD-measuring unit 350, a sludge tank 400 and a diluting unit 460.

The first COD-measuring unit 110, the second COD-measuring unit 250 andthe third COD-measuring unit 350 shown in FIG. 14 realize the functionof the COD-measuring unit 600 shown in FIG. 12. Further, a pH-adjustingunit 220 and a pH-adjusting unit 320 shown in FIG. 14 realize thefunction of the pH-adjusting unit 608 shown in FIG. 12. Furthermore, anadding unit 210 and an adding unit 310 shown in FIG. 14 realize thefunction of the adding unit 606 shown in FIG. 12.

The control tank 100 controls the wastewater, and transfers it to thefirst treatment tank 200. For example, the control tank 100 controls theflow rate, pH and temperature of the wastewater so that they aresuitable for the microorganism contained in the first treatment tank200.

The volume of the first treatment tank 200 and second treatment tank 300varies depending on the amount of wastewater. For example, the volume ofthe first treatment tank 200 and second treatment tank 300 is adjustedso that the total residence time of the wastewater in the firsttreatment tank 200 and second treatment tank 300 comes to about 0.2 dayto about 20 days. In particular, the volume of the first treatment tank200 and second treatment tank 300 is preferably adjusted so that thetotal residence time of the wastewater in the first treatment tank 200and second treatment tank 300 comes to about 0.5 day to about 5 days.The wastewater is stayed in the first treatment tank 200 for apredetermined period of time, and then, transferred to the secondtreatment tank 300. After further staying in the second treatment tankfor a predetermined period of time, the wastewater is transferred to thesludge tank 400.

The specific microorganism is added to both the first treatment tank 200and second treatment tank 300, or at least the second treatment tank300. The microorganism added degrades the hardly biodegradable materialcontained in the wastewater. The hardly biodegradable material is, forexample, an organic aminocarboxylic acid such as EDTA(ethylenediaminetetraacetic acid), DTPA (diethylenetriaminepentaaceticacid) or PDTA (1,3-propanediaminetetraacetic acid). Above all, EDTA isparticularly effective.

Further, the microorganism contained in the first treatment tank 200 ispreviously naturalized to wastewater having a higher concentration thanthe microorganism contained in the second treatment tank 300. Forexample, the first treatment tank 200 contains the microorganismnaturalized to wastewater having a COD concentration of 0.5 g/l to 20g/l. On the other hand, the second treatment tank 300 contains themicroorganism naturalized to wastewater having a COD concentration of0.3 g/l to 14 g/l. In this embodiment, the microorganism contained inthe first treatment tank 200 is one naturalized by staticallycultivating Bacillus editabidus-1 in a culture (pH 6.0) comprising 0.5%polypeptone, 0.1% yeast extract, 0.1% Cu-EDTA and 500 ml of 1/30 Mphosphate buffer, at 37.degree. C. for 7 days. The microorganismcontained in the second treatment tank 300 is one naturalized bystatically cultivating Bacillus editabidus-1 in a culture (pH 6.0)comprising 0.5% polypeptone, 0.1% yeast extract, 0.01% Cu-EDTA and 500ml of 1/30 M phosphate buffer, at 37.degree. C. for 7 days.

The first COD-measuring unit 110 measures the COD concentration of thewastewater before the wastewater is transferred from the control tank100 to the first treatment tank 200. The first COD-measuring unit 110 isinstalled, for example, in the vicinity of a wastewater inlet of thefirst treatment tank 200. Further, the first COD-measuring unit 110maybe installed in the control tank 100, as long as it is arranged insuch a position that it can measure the COD concentration of thewastewater before addition of the microorganism.

The second COD-measuring unit 250 measures the COD concentration of thewastewater just before the wastewater is transferred from the firsttreatment tank 200 to the second treatment tank 300. The secondCOD-measuring unit 250 is installed, for example, in the vicinity of awastewater inlet of the second treatment tank 300. Further, the secondCOD-measuring unit 250 may be installed in the first treatment tank 200or the second treatment tank 300, as long as it is arranged in such aposition that it can measure the COD concentration of the wastewaterjust before or just after the transfer of the wastewater from the firsttreatment 200 to the second treatment tank 300.

The third COD-measuring unit 350 measures the COD concentration of thewastewater when the wastewater is transferred from the second treatmenttank 200 to the sludge tank 400. The third COD-measuring unit 350 isinstalled in the vicinity of a wastewater outlet of the second treatmenttank 300. Further, the third COD-measuring unit 350 may be installed inthe second treatment tank 300 or in the sludge tank 400, as long as itis arranged in such a position that it can measure the COD concentrationof the wastewater after treatment in the second treatment tank 300.

The first treatment tank 200 further has the adding unit 210, thepH-adjusting unit 220, a stirring unit 230 and a filter 240. ThepH-adjusting unit 220 measures the pH of the wastewater in the firsttreatment tank 200, and adjusts the pH to a preliminarily establishedvalue. Here, the pH-adjusting unit 220 adjusts the pH to a valuesuitable for the microorganism added to the first treatment tank 200.For example, the pH-adjusting unit 220 adjusts the pH of the wastewaterin the first treatment tank 200 to about 6.0. The stirring unit 230stirs the wastewater in the first treatment tank 200. The stirring unit230 may be a unit that mechanically stirs the wastewater. In thisembodiment, the stirring unit 230 stirs the wastewater by aeration. Thefilter 240 separates the wastewater from the carrier on which themicroorganism is immobilized.

The adding unit 210 adds the nutriment for the microorganism to thefirst treatment tank 200, when degradability of the microorganism islowered. Specifically, when the factory terminal 30 receives theless-than-predetermined-value information from the central controldevice 20, the adding unit 210 adds the nutriment suitable for growth ofthe microorganism such as a carbon source, a nitrogen source, an organicnutrient source or nutriment source comprising an inorganic salt to thefirst treatment tank 200. As the organic nutrient sources, there can beadded, for example, polypeptones, yeast extract, meat extract andmolassses. Further, as the inorganic nutrient sources, there can beadded, for example, various types of phosphates and magnesium salts. Inthis case, the adding unit 210 adds the nutriment to the first treatmenttank 200 in an amount corresponding to the COD difference received fromthe central control device 20 by the factory terminal 30.

Further, when the adding unit 210 receives theless-than-predetermined-value information from the central controldevice 20 after addition of the nutriment for the microorganism, theadding unit adds the microorganism itself that degrades the hardlydegradable material contained in the wastewater to the first treatmenttank 200. In this case, the adding unit 210 adds the microorganism tothe first treatment tank 200, in an amount corresponding to the CODdifference received from the central control device 20 by the factoryterminal 30.

In this case, the adding unit 210 adds the microorganism to the firsttreatment tank 200, in an amount of 10 g to 50 kg by dry weight percubic meter of wastewater. More preferably, the adding unit 210 adds themicroorganism to the first treatment tank 200, in an amount of 20 g to5,000 g by dry weight per cubic meter of wastewater.

The second treatment tank 300 has the adding unit 310, the pH-adjustingunit 320, a stirring unit 330 and a filter 340. The adding unit 310 addsthe nutriment for the microorganism to the second treatment tank 300,when degradability of the microorganism in the second treatment tank 300is lowered. Specifically, when the difference between a CODconcentration measured by the second COD-measuring unit 250 and a CODconcentration measured by the third COD-measuring unit 350 is lower thana preliminarily determined value, the adding unit 310 adds the nutrimentsuitable for growth of the microorganism, such as a carbon source, anitrogen source, an organic nutrient source or a nutrient sourcecomprising an inorganic salt to the second treatment tank 300.

Further, even after addition of the nutriment for the microorganism,when the difference between a COD value measured by the secondCOD-measuring unit 250 and a COD value measured by the thirdCOD-measuring unit 350 is lower than a preliminarily determined value,the adding unit 310 adds the microorganism itself that degrades organicaminocarboxylic acids contained in the wastewater to the secondtreatment tank 300.

The constitution and operation of the pH-adjusting unit 320, thestirring unit 330 and the filter 340 are approximately similar to thoseof the pH-adjusting unit 220, the stirring unit 230 and the filter 240,so that descriptions thereof are omitted.

The sludge tank 400 stores sludge contained in the second treatment tank300, and discharges a supernatant of the wastewater to the outside.Further, the sludge tank 400 may complement the degradation treatment inthe first treatment tank 200 and the second treatment tank 300. That isto say, the sludge tank 460 may degrade and remove organic materials andinorganic materials that can not be treated in the first treatment tank200 and the second treatment tank 300.

The sludge tank 400 has a control unit 420, an aerating unit 430 and adrain pump 450. The control unit 420 infuses a neutralizing agent forneutralizing the wastewater and a nutritional supplement for themicroorganism contained in the sludge tank 400 into the sludge tank 400.The aerating unit 430 conducts aeration. The drain pump 450 dischargesthe supernatant of the wastewater in the sludge tank 400 to the outside.The drain pump 450 may have a drain inspection unit. The draininspection unit inspects the content of inclusions of a liquiddischarged by the drain pump 450. A diluting unit 460 dilutes thewastewater discharged by the drain pump 450 with dilution water.

The treatment tank 90 according to this embodiment has two tanks, thefirst treatment tank 200 and the second treatment tank 300, but may beone tank. Further, it may have more tanks. Furthermore, in thisembodiment, the factory terminal 30 calculates the amount of thenutriment added or the amount of the microorganism added, on the basisof the COD difference. However, any one of the addition of thenutriment, the amount of the sludge returned and the addition of themicroorganism may be selected on the basis of the COD difference.Instead of the factory terminal 30, the central control device 20 maycalculate the amount of the nutriment or microorganism added on thebasis of the COD difference.

FIG. 15 is a schematic view showing the treatment tank 90 connected tothe factory terminal 30. In this embodiment of the treatment tank 90, asingle tank is used. However, a partition is provided in the tank todivide the tank into two sections, and the tank is composed of a firstsection and a second section connected in series to each other. Thetreatment tank 90 comprises a control tank 100, a first COD-measuringunit 110, a first BOD-measuring unit 111, a beginning part (referred toas a first section) 200 of an activated sludge tank, a secondCOD-measuring unit 250, a second BOD-measuring unit 251, a latter part(referred to as a second section) 300 of the activated sludge tank, athird COD-measuring unit 350, a third BOD-measuring unit 351, a treatedwastewater control tank 460, a sludge tank 400 not shown in the figureand a diluting unit 470.

The first COD-measuring unit 110, the second COD-measuring unit 250 andthe third COD-measuring unit 350 shown in FIG. 15 realize the functionof the COD-measuring unit 600 shown in FIG. 13, and the firstBOD-measuring unit 111, the second BOD-measuring unit 251 and the thirdBOD-measuring unit 351 shown in FIG. 15 realize the function of theBOD-measuring unit 601 shown in FIG. 13. Further, a pH-adjusting unit220 and a pH-adjusting unit 320 shown in FIG. 15 realize the function ofthe pH-adjusting unit 608 shown in FIG. 13. Furthermore, an adding unit210 and an adding unit 310 shown in FIG. 15, each of which conductsaddition for both or at least one of COD correction and BOD correction,realize the functions of the adding unit I 606 for conducting additionfor COD correction and the adding unit II 607 for conducting additionfor BOD correction shown in FIG. 13.

The control tank 100 controls the wastewater, and transfers it to thefirst section 200 of the treatment tank. For example, the control tank100 controls the flow rate, pH and temperature of the wastewater so thatthey are suitable for the microorganism contained in the first section200 of the treatment tank.

The volume of the first section 206 and second section 300 of thetreatment tank varies depending on the amount of wastewater. Forexample, the volume of the first section 200 and second section 300 ofthe treatment tank is adjusted so that the total residence time of thewastewater in the first section 200 and second section 300 of thetreatment tank comes to about 0.2 day to about 20 days. In particular,the volume of the first section 200 and second section 300 of thetreatment tank is preferably adjusted so that the total residence timeof the wastewater in the first section 200 and second section 300 of thetreatment tank comes to about 0.5 day to about 5 days. The wastewater isstayed in the first section 200 of the tank for a predetermined periodof time, and then, transferred to the second section 300 of thetreatment tank. After further staying in the second section for apredetermined period of time, the wastewater is transferred to thesludge tank 400.

The specific microorganism is added to both the first section 200 andsecond section 300 of the treatment tank, or at least the second section300 of the treatment tank. The microorganism added degrades the hardlybiodegradable material contained in the wastewater. The hardlybiodegradable material is, for example, an organic aminocarboxylic acidsuch as EDTA (ethylenediaminetetraacetic acid), DTPA(diethylenetriaminepentaacetic acid) or PDTA(1,3-propanediaminetetraacet-ic acid) Above all, EDTA is particularlyeffective.

In this embodiment, the specific microorganism is a microorganismnaturalized by statically cultivating Bacillus editabidus-1 in a culture(pH 6.0) comprising 0.5% polypeptone, 0.1% yeast extract, 0.1% Cu-EDTAand 500 ml of 1/30 M phosphate buffer, at 37.degree. C. for 7 days.

The first COD-measuring unit 110 and the first BOD-measuring unit 111measure the COD value and the BOD value of the wastewater before thewastewater is transferred from the control tank 100 to the first section200 of the treatment tank. The first COD-measuring unit 110 and thefirst BOD-measuring unit 111 are installed, for example, in the vicinityof a wastewater inlet of the first section 200. Further, the firstCOD-measuring unit 110 and the first BOD-measuring unit 111 may beinstalled in the control tank 100, as long as they are arranged in sucha position that they can measure the COD and BOD values of thewastewater before addition of the microorganism.

The second COD-measuring unit 250 and the second BOD-measuring unit 251measure the COD value and the BOD value of the wastewater just beforethe wastewater is transferred from the first section 200 of thetreatment tank to the second section 300 of the treatment tank. Thesecond COD-measuring unit 250 and the second BOD-measuring unit 251 areinstalled, for example, in the vicinity of a wastewater inlet of thesecond section 300. Further, the second COD-measuring unit 250 and thesecond BOD-measuring unit 251 may be installed in an end portion of thefirst section 200, as long as they are arranged in such a position thatthey can measure the COD and BOD values of the wastewater just before,during or just after the transfer of the wastewater from the firstsection 200 to the second section 300.

The third COD-measuring unit 350 and the third BOD-measuring unit 351measure the COD value and the BOD value of the wastewater when thewastewater is transferred from the second section 200 to the wastewatercontrol tank 460. The third COD-measuring unit 350 and the thirdBOD-measuring unit 351 are installed in the vicinity of a wastewateroutlet of the second section 300. Further, the third COD-measuring unit350 and the third BOD-measuring unit 351 may be installed in an outletof the second section 300 or in the wastewater control tank 460, as longas they are arranged in such a position that they can measure the CODand BOD values of the wastewater after treatment in the second section300.

The first section 200 of the treatment tank further has the adding unit210, the pH-adjusting unit 220, a stirring unit 230 and a filter 240.The pH-adjusting unit 220 measures the pH of the wastewater in the firstsection 200, and adjusts the pH to a preliminarily established value.Here, the pH-adjusting unit 220 adjusts the pH to a value suitable forthe microorganism added to the first section 200. For example, thepH-adjusting unit 220 adjusts the pH of the wastewater in the firstsection 200 to about 6.0. The stirring unit 230 stirs the wastewater inthe first section 200. The stirring unit 230 may be a unit thatmechanically stirs the wastewater. In this embodiment, the stirring unit230 stirs the wastewater by aeration. The filter 240 separates thewastewater from the carrier on which the microorganism is immobilized.

The adding unit 210 adds activated sludge and/or the nutrient source forthe specific microorganism to the first section 200 of the treatmenttank, when degradability of the activated sludge or the specificmicroorganism is lowered. Specifically, when the factory terminal 30receives the less-than-predetermined-value information from the centralcontrol device 20, the adding unit 210 adds the nutrient source suitablefor growth of the specific microorganism such as a carbon source, anitrogen source, an organic nutrient source or a nutrient sourcecomprising an inorganic salt to the first section 200. As the organicnutrient sources, there can be added, for example, polypeptones, yeastextract, meat extract and molasses. Further, as the inorganic nutrientsources, there can be added, for example, various types of phosphatesand magnesium salts. In this case, the adding unit 210 adds the nutrientsource to the first section 200 in an amount corresponding to the CODdifference received from the central control device 20 by the factoryterminal 30.

Further, when the adding unit 210 receives theless-than-predetermined-value information from the central controldevice 20 after addition of the nutrient source for the biodegradingbacterium and/or the nutrient source for the specific microorganism, theadding unit increases the amount of returned sludge or adds the specificmicroorganism itself to the first section 200. In this case, the addingunit 210 increases the amount of returned sludge or adds the specificmicroorganism to the first section 200, in an amount corresponding tothe COD difference or the BOD difference received from the centralcontrol device 20 by the factory terminal 30.

In this case, the adding unit 210 adds the returned sludge or thespecific microorganism to the first section 200, in an amount of 10 g to50 kg by dry weight per cubic meter of wastewater. More preferably, theadding unit 210 adds the returned sludge or the specific microorganismto the first section 200, in an amount of 20 g to 5,000 g by dry weightper cubic meter of wastewater.

The second section 300 of the treatment tank has the adding unit 310,the pH-adjusting unit 320, a stirring unit 330 and a filter 340. Theadding unit 310 adds the nutrient source for the microorganism to thesecond section 300, when degradability of the activated sludge or thespecific microorganism in the second section 300 is lowered.Specifically, when the difference between a COD concentration measuredby the second COD-measuring unit 250 and a COD concentration measured bythe third COD-measuring unit 350 is lower than a preliminarilydetermined value, the adding unit 310 adds the nutrient source suitablefor growth of the microorganism, such as a carbon source, a nitrogensource, an organic nutrient source or a nutrient source comprising aninorganic salt to the second section 300 (the adding unit I 606 in FIG.13). Also in the section 300, the BOD-measuring unit 251 measures theBOD value, and when biodegradability is lowered, the nutrient source forthe activated sludge can be supplied in the same manner as in the firstsection (the adding unit II 607 in FIG. 13). However, generally, withrespect to the biodegradability, it is preferable to cope with by theaddition of the nutrient source described above and further the increasein the amount of the returned sludge.

Further, even after addition of the nutrient source for themicroorganism, when the difference between a COD value measured by thesecond COD-measuring unit 250 and a COD value measured by the thirdCOD-measuring unit 350 is lower than a preliminarily determined value,the adding unit 310 adds the specific microorganism itself that degradesorganic aminocarboxylic acids contained in the wastewater to the secondsection 300.

In addition, with respect to the BOD, it is preferable to cope with inthe first section as described above. However, when the differencebetween a BOD value measured by the second BOD-measuring unit 251 and aBOD value measured by the third BOD-measuring unit 351 is lower than apreliminarily determined value, the returned sludge may be added to thesecond section 300 to increase the amount of the biodegrading bacteriumin the second section of the activated sludge tank.

The constitution and operation of the pH-adjusting unit 320, thestirring unit 330 and the filter 340 are approximately similar to thoseof the pH-adjusting unit 220, the stirring unit 230 and the filter 240,so that descriptions thereof are omitted.

The wastewater control tank 460 stores sludge contained in the secondsection 300, and discharges a supernatant of the wastewater to theoutside. Further, the wastewater control tank 460 may complement thedegradation treatment in the first section 200 and the second section300. That is to say, the wastewater control tank 460 may degrade andremove organic materials and inorganic materials that can not be treatedin the first section 200 and the second section 300.

The wastewater control tank 460 has a control unit (not shown in thefigure), an aerating unit (not shown in the figure) and a drain pump450. The control unit infuses a neutralizing agent for neutralizing thewastewater and a nutritional supplement for the microorganism containedin the wastewater control tank 460 into the wastewater control tank 460.The aerating unit conducts aeration. The drain pump 450 discharges thesupernatant of the wastewater in the wastewater control tank 460 to theoutside. The drain pump 450 may have a drain inspection unit. The draininspection unit inspects the content of inclusions of a liquiddischarged by the drain pump 450. The wastewater control tank 460dilutes the wastewater discharged by the drain pump 450 with dilutionwater.

The treatment tank 90 according to this embodiment is the single tankcomprising two sections, the first section 200 and the second section300, but may be one tank having no partition. It may have two tanks inseries or more tanks. Further, in this embodiment, the factory terminal30 calculates the amount of the nutrient source added, the amount of thesludge returned or the amount of the specific microorganism added, onthe basis of the COD difference and the BOD difference. However, any oneof the addition of the nutrient source, the amount of the sludgereturned and the addition of the specific microorganism may be selectedon the basis of the COD difference and the BOD difference. Instead ofthe factory terminal 30, the central control device 20 may calculate theamount of the nutrient source or microorganism added on the basis of theCOD difference and/or the BOD difference.

FIG. 16 is a block diagram showing the hardware constitution of thecentral control device 20. The central control device 20 has a CPU 700,a ROM 702, a RAM 704, a communication interface 706, a display unit 708as an example of the output unit 502, a hard disk drive 710, a floppydisk drive 712, a floppy disk 714, a CD-ROM drive 716 and a CD-ROM 718.The CPU 700 operates on the basis of programs stored in the ROM 702 andthe RAM 704. The communication interface 706 communicates with thefactory terminal 30 through the network 10. The hard disk drive 710 asan example of a storing device stores setting information and a programby which the CPU 700 operates. Further, the communication interface 706may communicates with the factory terminal 30 through an exclusive line.The hard disk drive 710 connects to various data bases, and transmits orreceives data, thereby conducting writing, readout and renewal of thecontents.

The floppy disk drive 712 reads data or a program from the floppy disk714, and provide it to the CPU 700. The CD-ROM drive 716 reads data or aprogram from the CD-ROM 718, and provides it to the CPU 700. Thecommunication interface 706 connects to the network 10, and transmits orreceives data. The display unit 708 displays image data or results oftotaling.

Software executed by the CPU 700 is provided to a user in a state whereit is stored in a recording medium such as the floppy disk 714 or theCD-ROM 718. The software stored in the recording medium may be eithercompressed or uncompressed. The software is installed from the recordingmedium in the hard disk drive 710, read out to the RAM 704 and executedby the CPU 700.

The software stored in the recording medium and provided, that is tosay, the software installed in the hard disk drive 710 has the receivingfunction, the output function, the totaling function, the photographedimage-obtaining function, the pH value-obtaining function, the judgingfunction, the COD-obtaining function, the computing function, thecomparison function, the processing function, the input function, theimage control function, the measured value control function and thepredetermined value control function as the functional constitution.These respective functions work on the computer to allow it to conductprocessing, which is the same as the functions and operation of thecorresponding members in the central control device 20 in thisembodiment. Accordingly, descriptions thereof are omitted.

In the floppy disk 714 or the CD-ROM 718 shown as an example in FIG. 16,a part of the operation or all functions of the central control device20 in all embodiments described in this specification can be stored.

The program may be directly read out from the recording medium to theRAM to execute it, or after the program is once installed in the harddisk drive, it may be read out to the RAM to execute it. Further, theabove-mentioned program may be stored either in a single recordingmedium or in a plurality of recording media. Furthermore, a modulestored in the recording medium may provide the respective functions incooperation with an operating system. For example, it may be applied tothe operating system to conduct a part or all of the functions, and thefunctions may be provided on the basis of a reply from the operatingsystem.

The program or module shown above may be stored in an external recordingmedium. As the recording media, there are available an optical recordingmedium such as a DVD or a PD, a magnetic optical recording medium suchas an MD, a tape medium, a magnetic recording medium and a semiconductormemory such as an IC card or a miniature card, as well as the floppydisk and the CD-ROM. Further, a storing device such as a hard disk or aRAM mounted in a server system connected to an exclusive communicationnetwork or an internet maybe used as the recording medium, and theprogram may be provided to the central control device 20 through thenetwork.

FIG. 17 is a block diagram showing the hardware constitution of thefactory terminal 30. The factory terminal 30 has a CPU 800, a ROM 802, aRAM 804, a communication interface 806, an interface 808 for varioustypes of measurement, a hard disk drive 810, a floppy disk drive 812,and CD-ROM drive 816. The CPU 800 operates on the basis of programsstored in the ROM 802 and the RAM 804. The communication interface 806communicates with the factory terminal 30 through the communicationnetwork 10. The hard disk drive 810 as an example of a storing devicestores setting information and a program by which the CPU 800 operates.Further, the communication interface 806 may communicates with thefactory terminal 30 through an exclusive line. The hard disk drive 810connects to various data bases, and transmits or receives data, therebyconducting writing, readout and renewal of the contents. The interface808 for various types of measurement receives data from variousmeasuring devices 809 or transmits it. The various measuring devices 809measure the COD value, the BOD value and the pH value. Further, thevarious measuring devices 809 include a function of an imaging devicethat photographs a state in the treatment tank.

The floppy disk drive 812 reads data or a program from the floppy disk814, and provide it to the CPU 800. The CD-ROM drive 7816 reads data ora program from the CD-ROM 818, and provides it to the CPU 800. Thecommunication interface 806 connects to the network 10, and transmits orreceives data.

Software executed by the CPU 800 is provided to a user in a state whereit is stored in a recording medium such as the floppy disk 814 or theCD-ROM 818. The software stored in the recording medium may be eithercompressed or uncompressed. The software is installed from the recordingmedium in the hard disk drive 810, read out to the RAM 804 and executedby the CPU 800.

The software stored in the recording medium and provided, that is tosay, the software installed in the hard disk drive has the receivingfunction, the transmitting function, the COD-measuring function, thepH-measuring function, the imaging function, the adding function, thepH-adjusting function, the display function and the processing functionas the functional constitution. These respective functions work on thecomputer to allow it to conduct processing, which is the same as thefunctions and operation of the corresponding members in the factoryterminal 30 in this embodiment. Accordingly, descriptions thereof areomitted.

In the floppy disk 814 or the CD-ROM 818 shown as an example in FIG. 17,a part of the operation or all functions of the factory terminal 30 inall embodiments described in this specification can be stored.

The program may be directly read out from the recording medium to theRAM to execute it, or after the program is once installed in the harddisk drive, it may be read out to the RAM to execute it. Further, theabove-mentioned program may be stored either in a single recordingmedium or in a plurality of recording media. Furthermore, a modulestored in the recording medium may provide the respective functions incooperation with an operating system. For example, it may be applied tothe operating system to conduct a part or all of the functions, and thefunctions may be provided on the basis of a reply from the operatingsystem.

The program or module shown above may be stored in an external recordingmedium. As the recording media, there are available an optical recordingmedium such as a DVD or a PD, a magnetic optical recording medium suchas an MD, a tape medium, a magnetic recording medium and a semiconductormemory such as an IC card or a miniature card, as well as the floppydisk and the CD-ROM. Further, a storing device such as a hard disk or aRAM mounted in a server system connected to an exclusive communicationnetwork or an internet may be used as the recording medium, and theprogram may be provided to the factory terminal 30 through the network.

Although the invention has been described above with reference topreferred embodiments, it is to be understood that the scope of theinvention is not limited to the description of the embodiments describedabove. Various modifications and improvements can be made in theembodiments described above. For example, in the central control systemaccording to this embodiment, the factory terminal 30 connects to thetreatment tank 90, and instructs addition of the nutrient source and thelike. Instead of this, however, central control device 20 may directlyconnect to the treatment tank 90, and may instruct addition of thenutrient source and the like. It will be apparent from the descriptionof the appended claims that embodiments in which such modifications andimprovements are made are also within the scope of the invention.

As apparent from the above-mentioned description, according to thewastewater treatment control system of the invention, the wastewatercontaining a specific compound such as the hardly biodegradable compoundcan be effectively treated using the microorganism. In particular, whenthe wastewater containing the hardly biodegradable compound is treated,both can be reduced with high effectiveness.

The entire disclosure of each and every foreign patent application fromwhich the benefit of foreign priority has been claimed in the presentapplication is incorporated herein by reference, as if fully set forth.

1. A method of accounting for a wastewater treatment service with awastewater treatment control system for controlling a treatment tank fortreating wastewater with a microorganism that can degrade a specificcompound, wherein the wastewater treatment control system includes aterminal for obtaining data relating to the treatment tank and a centralcontrol device communicating with the terminal through a network,wherein the terminal has a concentration-measuring unit for measuring aconcentration value corresponding to a concentration of the specificcompound in the treatment tank and has a transmitting unit fortransmitting the concentration value measured by theconcentration-measuring unit to the central control device, and whereinthe central control device receives the concentration value of thetreatment tank from the terminal, the method comprising: accounting inproportion to a reduction in cost by an introduction of the wastewatertreatment system, compared to a cost previously required for drainingthe wastewater.
 2. A method of accounting for a wastewater treatmentservice with a wastewater treatment control system for controlling awastewater treatment of using an activated sludge tank containing amicroorganism that can degrade a hardly biodegradable compound, whereinthe wastewater treatment control system includes a measuring unit formeasuring a BOD value and a characteristic value corresponding to aconcentration of the hardly biodegradable compound in wastewater and acontrolling unit for controlling the wastewater treatment on the basisof the BOD value and the characteristic value, the method comprising:accounting in proportion to a reduction in treatment cost by anintroduction of the wastewater treatment system, compared to a treatmentcost previously required for draining the wastewater.